Other Parts Discussed in Thread: BQ24079, TPS22915
Dear TI,
Is there an easy way to implement shipping mode with bq25050 with activation both by button press and USB charger connection? Or just by USB connection only?
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Hello Dmitry,
You can get the lowest battery iq by pulling CHG to GND while in battery discharge mode. This is possible with push button or MCU -- when adapter is plugged in you would need to remove the pulldown to get correct charge status reading.
See IBAT(PDWN) in the spec.
Thanks,
Nick
Hi Dmitry,
By shipping mode, you're asking if the device can be made so that battery is present but the OUT is off or not powered. Is that correct? Nick is correct in that the lowest battery Iq is obtained pulling CHG to GND in battery discharge mode but I thought I'd gather more information. There may be some extra stuff with the BGATE pin but I'll need some time in the lab to see if this is possible while maintaining device functionality.
We've written an application note implementing shipping mode for a few devices in the BQ2407X family such as the BQ24079 (check that out here: https://www.ti.com/lit/ug/sluaa18/sluaa18.pdf).
We've also recently released an I2C linear charger that has shipping mode built in the device: https://www.ti.com/product/BQ25180
Best Regards,
Anthony Pham
Hi Nick,
thanks a lot. Am I correctly follow you that CHG pull-down leads only to TS current source shutdown and doesn't mean that battery is fully disconnected from the system?
Hi Anthony,
That should be a nice device but we have limited project time (and 25180 still is out of stock). Also due to DFM recommendations we're looking for solution with at least 0.5 mm pads spacing. Just as is.
Looking forward for your suggestions about using external FET with 25050 for shipping mode support.
Hi Dmitry,
Am I correctly follow you that CHG pull-down leads only to TS current source shutdown and doesn't mean that battery is fully disconnected from the system?
Yes, that is correct.
Best Regards,
Anthony Pham
Hi Dmitry,
Looking forward for your suggestions about using external FET with 25050 for shipping mode support.
Understood! Let me schedule some lab time to take a look at what we can do with the BQ25050.
Best Regards,
Anthony Pham
Hi Dmitry,
Take a look at this application note that I've linked below using the TPS22915 load switch. This will allow you to implement shipmode into the charger.
Keep in mind, you'll need to connect the VIN of the TPS22915B to the OUT of the BQ25050.
Let me know if you have any further questions!
Implementing Ship Mode using the TPS22915B Load Switch: https://www.ti.com/lit/an/slva821/slva821.pdf
Best Regards,
Anthony Pham
Dear Anthony,
thank you for the suggestion.
Is that correct that here is no chance to use only external MOSFET to BGATE + (perhaps) some little logic to do this?
Hi Dmitry,
Our office is closed in observance the Presidents Day Holiday. We will get back to you by 02/23 after we return to the office.
Best regards,
Eric
Hi Dmitry,
The issue is the current that would be leaking from the body diode of the external MOSFET. As long as the voltage from BAT to OUT is above the threshold for this diode, there will be a current path from BAT to OUT. The current will depend on the FET that is used while with the Ship Mode app note shows a 500 nA consumption.
Best Regards,
Anthony Pham